Process of treating hard water



Patented Sept. 13, 1927.

UNITED STATES PATENT OFFICE. 7

.eareoar rumors, or MOSCOW, RUSSIA, 'AND mu snasraxorr, or rams, amen.

raocnss or rum-me naan wanna.

Io Drawing.

This invention relates to processes for treating water and it comprisesa process in which hard water, that is, water which contains insolution, salts ofalkaline earth metals, is. treated. with highmolecular weight sulphonic acids for the purpose of softening the water.

Various. 'rocesses for softening hard the dissolved calcium and.magnesium com-' pounds which give the water its hard char-.-

acteristics. Itis to be noted that all of these processes contemplatesoftening the water before it is put into industrial use.

We have discovered a way in which hard water,.that is, water containingcalcium and magnesium salts in solution, usually in the form of theirbicarbonates, may be softened without the necessity of using baseexchanging substances andwithout the necessity of adding salts to thewater to precipitate the calcium and magnesium salts as insolublecarbonates, -.Which latter process re uires filtering out the insolubleprecipitate cal-- 0mm and magnesium salts.

We have found, that the addition of hi h molecular weight sulphonicacids to t e hard water, in suflicient quantity toj'react 4 with all ofthe calcium and magnesium present in the water to form calcium and.

magnesium sulphonates, will completely soften the water. Furthermore. itis unnecessary to remove the calcium and magnesium sulphonates so formedprior to the use of the water in laundries,dyeing, flax wetting, etc. YThis, we have discovered is due to. the fact thatthe calcium andmagnesium sul honates so formed, while-the are insolub e in the water,remain in a co loidal, or ultra-microscopic state and do nothave anyundesirable efiects on the materials treated with the softened water.Such water, softened by the addition of s h 5 molecularweight sulphonicacids, may

. used in many casesin lieu 'of distilled water.-

rmutite and other Application and December :0, 1m. Serial nuisance.

The chemical reactions occurring in hard 'water when high molecularweight sulphonic acids are added thereto are comparatively simple. Allofthe alkaline earth metal carhonates and bicarbonates are decomposed bythe sulphonic acids with the formation of alkaline earth metalsulphonates and the liberation of carbon dioxlde. With calciumbicarbonates, for instance, the calcium salt ofthe high molecular weightsul honic acid is formed and, though it is inso uble, it remains in thesolution in a colloidal state. With calcium salts and salts of evenhigher valency, corresponding sulphonates are formed.

It will thus be seen that our process for softeningwater merely consistsin adding a high molecular weight sulphonic acid tothe hard water insufiicient quantity to react with all of the hardening constituents,that is, the calcium and magnesium salts, to form correspondingsulphonates. In this way the water is effectively softened without theneg0.

cessity of filtering operations.

The high molecular wei ht sulphonicacids which we have foun thosederived from the sulphonation of various oils and aromatic compounds,such. as, naphtha .distillates, aromatic hydrocarbons, phenols,turpentine oil, distillates derived suitable are from brown-coal tar,etc. .And by high molecular weight sulphonic acids in the descriptionand in the appended claims we mean to include sul honic acid derivativesof these substances. ost of the sulphonates are of. uncertainconstitution, but they are all derived by sulphonating variouscomparatively high mo ecular weight aliphatic and aromatic,hydrocarbons.

The quantity of sulphonic acids to be added to the hard water, ofcourse, depends upon the degree of hardness. As a practical matter, aquantity of sulphonic acids must be added to'the water suflicient toreact with all of-the hydroxides, carbonates, and

,bicarbonates of magnesium, calcium, iron and other hardeningconstitutents contained in the water; In order to be sure that thewateris com letely softened, it is advantageous to ad the-sul honic"acids in such quantity that a fart r addition would cause a weak acidreaction ,with methylorange indicator.

The particular sulphonic acids employed may be derived from aromatic orahphatic sources. In every case however, these sulphonic acids which aresuitable will be such acids as will give insoluble alkaline earth metalsalts capable of remaining in the colloidal state in water.

What we claimis:

1. In the rocess of softenin hard water, the step whlch comprises treatmthe water with high molecular Wei ht sulp onic acids.

2. In the process of so tening hard water, the step which comprisesadding 'hi h molecular Wei ht sulphonic acids to t e water in quantitysuflicieut to react with all of the alkaline earth metal salts dissolvedin said water to form alkaline earth metal sulphonates.

3. In the process of softenin hard water, the step which comprises ad mgaromatic sul honic acids to said water in uantit su cient to react withall of the hardenin constituents in said water to form colloida metallicsulphonates but in quantity insufficient to ive more than a faintly acidreaction to t e water.

4. In the process of softenin hard water the step which comprises ad inga small quantity of naphthol sulphonic acid to said water in quantitysufiicient to react with all the hardening constituents in said water,and leave the water neutral.

tures.

GRIGORI PETROFF. PETER SHESTAKOF F In testimony whereof we afiix oursigna- 80

